13G Filing: Blue Mountain Capital and Avista Healthcare Public Acquisiton Corp (AHPA)

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CUSIP No. G0726L109		13G		Page 4 of 6 Pages

Item 1.

(a)

Name of Issuer

Avista Healthcare Public Acquisition Corp.

(b)

Address of Issuers principal executive offices

65 East 55th Street, 18th Floor,
New York, New York 10022

Item 2.

(a)

Name of person filing

This Amendment No. 1 (this Amendment) to
the Schedule 13G filed on October 19, 2016 is being filed on behalf of BlueMountain Capital Management, LLC (BMCM) and Blue Mountain Credit Alternatives Master Fund L.P. (BMCA) with respect to the shares of
Class A Ordinary Shares, $0.0001 par value per share (the Ordinary Shares), of Avista Healthcare Public Acquisition Corp., a Cayman Islands exempted company (the Issuer).

BMCM, which is the beneficial owner of 1,623,446 shares of Ordinary Shares, acts as investment manager to, and exercises investment discretion
with respect to the following beneficial owners of Ordinary Shares (each, a BlueMountain Fund):

(i)

BlueMountain Foinaven Master Fund L.P., a Cayman Islands exempted limited partnership, with respect to the 86,800 shares of Ordinary Shares directly owned by it;

(ii)

BlueMountain Montenvers Master Fund SCA SICAV-SIF, an investment company with variable capital organized as a specialized investment fund in the form of a corporate partnership limited by shares under the laws of Luxembourg, with respect to the 187,509 shares of Ordinary Shares directly owned by it;

(iii)

BlueMountain Guadalupe Peak Fund L.P., a Delaware limited partnership, with respect to the 61,600 shares of Ordinary Shares directly owned by it; and

(iv)

BlueMountain Kicking Horse Fund L.P., a Cayman Islands exempted limited partnership, with respect to the 81,363 shares of Ordinary Shares directly owned by it.

The filing of this statement should not be construed as an admission that BMCM is, for the purpose of Section 13 of the Act, the
beneficial owner of the Ordinary Shares owned by the BlueMountain Funds.

(b)

Address or principal business office or, if none, residence

280 Park Avenue, 12th
Floor, New York, New York 10017

(c)

Citizenship

See Row 4 of each Cover Page.

(d)

Title of class of securities

Class A Ordinary Shares, par value $0.0001 per share

(e)

CUSIP No.

G0726L109

Item 3. If this statement is filed pursuant to §§240.13d-1(b) or
240.13d-2(b) or (c), check whether the person filing is a:

(a)

☐ Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b)

☐ Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c)

☐ Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).